Visible Light Absorption Capacity Research Articles

Interlayer Potassium Single-Atom-Coordinated g-C3N4 for Significantly Boosted Visible Light Photocatalytic H2 Production.

In recent years, graphitic carbon nitride (g-C3N4) has attracted considerable attention because it includes earth-abundant carbon and nitrogen elements and exhibits good chemical and thermal stability owing to the strong covalent interaction in its conjugated layer structure. However, bulk g-C3N4 has some disadvantages of low specific surface area, poor light absorption, rapid recombination of photogenerated charge carriers, and insufficient active sites, which hinder its practical applications. In this study, we design and synthesize potassium single-atom (K SAs)-doped g-C3N4 porous nanosheets (CM-KX, where X represents the mass of KHP added) via supramolecular self-assembling and chemical cross-linking copolymerization strategies. The results show that the utilization of supramolecules as precursors can produce g-C3N4 nanosheets with reduced thickness, increased surface area, and abundant mesopores. In addition, the intercalation of K atoms within the g-C3N4 nitrogen pots through the formation of K-N bonds results in the reduction of the band gap and expansion of the visible-light absorption range. The optimized K-doped CM-K12 nanosheets achieve a specific surface area of 127 m2 g-1, which is 11.4 times larger than that of the pristine g-C3N4 nanosheets. Furthermore, the optimal CM-K12 sample exhibits the maximum H2 production rate of 127.78 μmol h-1 under visible light (λ ≥ 420 nm), which is nearly 23 times higher than that of bare g-C3N4. This significant improvement of photocatalytic activity is attributed to the synergistic effects of the mesoporous structure and K SAs doping, which effectively increase the specific surface area, improve the visible-light absorption capacity, and facilitate the separation and transfer of photogenerated electron-hole pairs. Besides, the optimal sample shows good chemical stability for 20 h in the recycling experiments. Density functional theory calculations confirm that the introduction of K SAs significantly boosts the adsorption energy for water and decreases the activation energy barrier for the reduction of water to hydrogen.

Enhanced Photocatalytic Degradation of Tetracycline by Magnetically Separable g-C3N4-Doped Magnetite@Titanium Dioxide Heterostructured Photocatalyst

Residual drug pollutants in water environments represent a severe risk to human health, so developing a cheap, environmentally friendly, and effective photocatalyst to deal with them has become a hot topic. Herein, a magnetically separable Fe3O4@TiO2/g-C3N4 photocatalyst with a special heterojunction structure was fabricated, and its photocatalytic performance was assessed by degrading tetracycline (TC). Compared to Fe3O4@TiO2, the synthesized Fe3O4@TiO2/g-C3N4 exhibited superior TC degradation performance, which was primarily ascribed to the heterojunction formed between TiO2 and g-C3N4 and its ability to enhance the visible light absorption capacity and reduce the photoinduced electron/hole recombination rate. Moreover, a free radical capture experiment further confirmed that·O2− and h+ are the predominant components in the TC degradation reaction. Under UV–Vis irradiation, the TC degradation rate escalated to as high as 98% within 120 min. Moreover, Fe3O4@TiO2/g-C3N4 was demonstrated to be easily recovered by magnetic separation without any notable loss even after five cycles, showing exceptional stability and reusability. These findings indicate that Fe3O4@TiO2/g-C3N4 is a promising photocatalyst for environmental remediation that may provide a sustainable approach to degrading antibiotic pollutants in wastewater.

Advanced IGZO Phototransistor Arrays: Enhancing Visible Light Detection Through Selectively Electrohydrodynamic Jet‐Printed Photocatalytic Layer Formation

AbstractExploring new horizons in phototransistors with an emphasis on mass customization is essential. Herein, a method for enhancing the performance of indium‐gallium‐zinc‐oxide (IGZO) phototransistors by incorporating a selectively formed tungsten trioxide (WO3) photocatalytic layer, utilizing electrohydrodynamic (EHD) jet‐printing is proposed. This approach aims to achieve significant manufacturing advantages and enhance functionality. An oxidizing solution of hydrogen peroxide (H2O2) doped with hydroxyethyl cellulose (HEC) is introduced to selectively oxidize tungsten (W) electrodes. In this mixture, H2O2 is responsible for the selective oxidation of W, whereas HEC contributes to the viscosity regulation and the formation of subgap states. The resulting selectively oxidized photocatalytic layer significantly expands its visible light absorption capacity to red light. Therefore, the optimized device, particularly under red light (635 nm) 5 mW mm−2, shows a remarkable enhancement in its optoelectronic characteristic: photoresponsivity increases from 29.71 to 124.54 A W−1, photosensitivity from 1.99 × 10‐1 to 1.79 × 104, and detectivity from 1.31 × 107 to 1.98 × 108 Jones compared to IGZO phototransistors without selectively oxidized photocatalytic layer. This advancement not only enhances the visible light detection capacity but also minimizes the persistent photoconductance issue inherent in IGZO devices. The demonstration of 6 × 6 phototransistor array illustrates the potential for image sensor applications, showcasing the practicality of mass customization.

Direct Z-scheme charge transfer Bi2O3/UiO-66-NH2 heterojunctions for boosted photocatalytic degradation of tetracycline hydrochloride in different water systems

The development of hybrid heterostructure photocatalysts with enhanced visible light absorption capacity holds significant importance in environmental remediation. However, the challenge persists in exploiting strong visible-light responsive photocatalysts with both high efficiency and stability. Herein, we successfully synthesized a hybrid Z-scheme heterojunction of Bi2O3 and UiO-66-NH2 (Bi2O3/UiO-66-NH2) through a simple hydrothermal route. The visible light photocatalytic performance of Z-scheme Bi2O3/UiO-66-NH2 heterojunction is systematically evaluated for persistent antibiotic tetracycline hydrochloride (TC-HCl) both in the clean and real water matrix. All heterojunction catalysts exhibit superior photodegradation capabilities compared to pristine Bi2O3 and UiO-66-NH2. The optimal ratio of the two components heterojunction (BUN-150), in particular, demonstrates the highest removal efficiencies for TC-HCl (95 %) within a 90-min timeframe. This remarkable photocatalytic performance is credited to the Z-scheme charge transfer occurring at the interface of Bi2O3 and UiO-66-NH2 in Bi2O3/UiO-66-NH2 heterojunction. The active species experiments and electron paramagnetic resonance analyses are conducted to identify the active reactive species during the TC-HCl degradation (·OH, h+, and ·O2−), and a precise photocatalytic degradation mechanism is explained. Additionally, the photodegradation intermediates of TC-HCl are detected using the HPLC-MS analysis to explain the degradation pathways of TC-HCl. This research paves the way for the development of novel Z-scheme Bi2O3-based heterojunction catalysts for outstanding photocatalytic applications.

Enhanced photocatalytic hydrogen evolution performance of Pd/g-C3N4 with carbon vacancies

Exploration of highly active, stable and environmentally friendly photocatalytic materials is key to address the problem for hydrogen production by photocatalytic water splitting. Among all the photocatalysts, graphitic carbon nitride (g-C3N4) has gained attention for its stable graphite-like electronic structure, appropriate band gap (∼2.7 eV), and high stability. However, the limited visible light absorption capacity and fast recombination of electron-hole pairs severely limit the photocatalytic performance of g-C3N4. In this study, Pd/g-C3N4 Schottky heterojunctions with carbon vacancies were prepared by an impregnation method. The surface plasmon resonance (SPR) effect of Pd0 nanoparticles and the incorporation of carbon vacancies synergistically reduce the band gap of g-C3N4, expanding its light response absorption capacity and increasing surface active sites, as a result of these modifications, the separation of electron-hole pairs is effectively improved, and photocatalytic water splitting for hydrogen production is greatly enhanced. Photocatalytic performance of Pd/g-C3N4 photocatalysts demonstrate outstanding hydrogen evolution efficiency under solar light irradiation. A convincing mechanism for the enhanced photocatalytic performance of the Pd/g-C3N4 Schottky heterojunctions was suggested. This investigation emphasizes a straightforward and efficient approach for fabricating of based g-C3N4 composite materials with exceptional photocatalytic efficiency.

Efficient photocatalytic hydrogen peroxide production over S-scheme In2S3/molten salt modified C3N5 heterojunction

Graphitic phase carbon nitride (g-C3N5), as a novel n-type metal-free material, is employed as a visible light-receptive catalyst because of its narrow band gap and abundant nitrogen. To overcome the low carrier mobility efficiency of g-C3N5, its modification by K ions was adopted. In addition, In2S3 was selected to couple with modified g-C3N5 to overcome the recombination of photogenerated e−/h+. As a novel photocatalytic material, it was proven to possess a high visible light absorption capacity and a strong H2O2 production ability (up to 3.89 mmol⋅L-1 in 2 h). Moreover, a S-scheme heterojunction structure was successfully constructed between the two materials, which was tested and confirmed to be successful in raising the photogenerated e−/h+ separation efficiency. Ultimately, the primary processes of photocatalytic H2O2 production were summarized by superoxide radical and rotating disc electron measurements. This research provides a fresh perspective for the synthesis of C3N5-based S-scheme heterojunction photocatalysts for producing H2O2.

Combustion synthesis of Ce/Mg co-doped ZnO nanoparticles as a visible-light-driven photocatalyst

ZnO and Ce/Mg co-doped ZnO nanoparticles as a visible-light-driven photocatalyst were synthesized by combustion method. X-ray diffraction (XRD) patterns of ZnO and Ce/Mg co-doped ZnO samples were indexed to the pure phase of hexagonal wurtzite ZnO structure without impurity detection. The Raman analysis of ZnO and Ce/Mg co-doped ZnO samples showed optical phonon E2H, A1(TO), E2L, E2H–E2L, A1(LO) and E1(LO) modes of wurtzite ZnO structure, including the detection of Zn−O stretching mode containing in FTIR spectra of hexagonal wurtzite ZnO. Transmission electron microscopic (TEM) images of ZnO and Ce/Mg co-doped ZnO samples showed uniform and good distribution of nanoparticles with different orientations. The photocatalysis of ZnO and Ce/Mg co-doped ZnO nanoparticles was studied through the degradation of methylene blue (MB) illuminated by visible radiation. In this research, the Zn0.97Ce0.015Mg0.015O nanoparticles have the highest efficiency of 95.16% within 150 min because of the largest specific surface area, smallest crystallite size and highest absorption capacity of visible light for active species production in degrading of MB under visible light. Photocatalytic mechanism of Ce/Mg co-doped ZnO nanoparticles in degrading MB was also proposed.

Tailoring the morphology and charge transfer pathways of ultrathin Cd0.8Zn0.2S nanosheets via ionic liquid-modified Ti3C2 MXenes towards remarkable photocatalytic hydrogen evolution

Small-sized CdxZn1–xS solid solution nanomaterial is an important candidate for efficient photocatalytic hydrogen evolution (PHE), but it still suffers from easy agglomeration, severe photo corrosion, and fast photogenerated electron-hole recombination. To tackle these issues, herein, we propose a new strategy to modify CdxZn1–xS nanoreactors by the simultaneous utilization of ionic-liquid)-assisted morphology engineering and MXene-incorporating method. That is, we designed and synthesized a novel hierarchical Cd0.8Zn0.2S/Ti3C2 Schottky junction composite through the in-situ deposition of ultrathin Cd0.8Zn0.2S nanosheets on unique IL-modified Ti3C2 MXenes by a one-pot solvothermal method for efficiently PHE. The unique construction strategy tailors the thickness of ultrathin Cd0.8Zn0.2S nanosheets and prevents them from stacking and agglomeration, and especially, optimizes their charge transfer pathways during the photocatalytic process. Compared with pristine Cd0.8Zn0.2S nanosheets, Cd0.8Zn0.2S/Ti3C2 has abundant photogenerated electrons available on the Ti3C2 surface for proton reduction reaction, owing to the absence of deep-trapped electrons, suppression of electron-hole recombination in Cd0.8Zn0.2S and high-efficiency charge separation at the Cd0.8Zn0.2S/Ti3C2 Schottky junction interface. Moreover, the hydrophilicity, electrical conductivity, visible-light absorption capacity, and surficial hydrogen desorption of Cd0.8Zn0.2S/Ti3C2 heterostructure are significantly improved. As a result, the heterostructure exhibits outstanding photocatalytic stability and super high apparent quantum efficiency, being rendered as one of the best noble-metal-free Cd-Zn-S-based photocatalysts. This work illustrates the mechanisms of morphology control and heterojunction construction in controlling the catalytic behavior of photocatalysts and highlights the great potential of the IL-assisted route in the synthesis of high-performance MXene-based heterostructures for photocatalytic hydrogen evolution.

Rational construction and significantly improved sonophotocatalytic performance of ZnIn2S4/Bi25FeO40 composites for the removal of organic pollutant

In this work, ZnIn2S4/Bi25FeO40 (ZIS/BFO) composites were prepared via a hydrothermal synthesis followed by ultrasound sonication method. Owing to the introduction of BFO, the obtained ZIS/BFO composites exhibited a higher visible-light absorption capacity than ZIS, which was revealed by the results of the diffusion reflectance spectra (DRS). Taking tetracycline hydrochloride (TCH) as the target pollutant, the decomposition experiments were conducted under ultrasonic coupling with visible-light irradiation to assess the sonophotocatalytic performance of the as-obtained catalysts. The results showed that the removal efficiency of BFO/ZIS composites was significantly improved compared with that of pure BFO and ZIS catalysts. Moreover, the loading amount of Bi25FeO40 imposed a substantial effect on the removal efficiency of TCH, namely that the removal efficiency of TCH first increased with the augment of loading amount, and declined thereafter. Specifically, the degradation rate of TCH reached up to 93.5% over ZIS/BFO composites with 10 wt% loading amount of Bi25FeO40. According to the results of radical scavenging experiments and electrochemical measurements, the proposed migration and separation pathway of charge carriers were put forward, and the possible enhancement mechanism toward sonophotocatalytic removal of TCH was achieved over ZIS/BFO catalysts. The significant improvement of the sonophotocatalytic performance over ZIS/BFO composites was mainly imputed to the synergistic effect of the improved visible-light absorption capacity and elevated sono/photo-activated charge transfer rate.

Efficient photocatalytic hydrogen generation by CeCO3OH/TiO2 composites

Due to its low photogenerated carrier separation efficiency and wide band gap, the photocatalytic activity of TiO2 is not ideal. In this work, CeCO3OH/TiO2 composites were successfully prepared by a simple hydrothermal method. A series of characterisations shows that the CeCO3OH/TiO2 composites improves the photogenerated carrier separation efficiency, narrowes the band gap width and increases the visible light absorption capacity compared with the monomer, enhancing the photocatalytic hydrogen evolution performance. Under visible light irradiation, 20% CeCO3OH/TiO2 exhibites the highest photocatalytic hydrogen production performance of 2386.16 μmol g−1 h−1, which is 18.7 times higher than that of pure TiO2 and 25.8 times higher than that of pure CeCO3OH. It provides ideas for the development of more efficient photocatalytic materials and technologies.

CaFe2O4/Ag/ZnO z-scheme heterojunction material for photocatalytic decomposition of ciprofloxacin

The Z-type heterojunction CaFe2O4/Ag/ZnO composite photocatalyst was successfully synthesized by the microwave-assisted hydrothermal methods. The photocatalytic activity of the CaFe2O4/Ag/ZnO was evaluated by the degradation of ciprofloxacin (CIP). The characterization results indicated that Ag doping can decrease the band gap (Eg) of ZnO and enhance its visible light absorption capacity. Ag/ZnO forms a Z-type heterojunction with CaFe2O4, which can significantly promote effective photogenerated carrier separation and enhance the visible light catalytic activity of the CaFe2O4/Ag/ZnO composite catalyst. It was observed that the degradation effect of the CaFe2O4/Ag/ZnO on CIP was significantly better than pure ZnO and CaFe2O4.

Metal-free thiophene-based covalent organic frameworks achieve efficient photocatalytic hydrogen evolution by accelerating interfacial charge transfer

Photocatalysis is widely recognized as an efficient and environmentally friendly pathway for the conversion of solar energy into chemical energy. In recent years, designing efficient hydrogen evolution to obtain green clean energy has been one of the major challenges faced by researchers. Covalent organic frameworks (COFs) are considered as new and effective photocatalyst due to the inherent porosity, high crystallinity and structural adjustability. In this study, two metal-free thiophene-based covalent organic frameworks (JLNU-308 and JLNU-309) were constructed by solvothermal method through effective modulation sites. Because JLNU-COFs has a narrow band gap and good absorption capacity in the spectral range, the interfacial charge transfer speed is accelerated to solve the problem of low charge separation efficiency. Remarkably, JLNU-309 displays an impressive hydrogen evolution rate of 2868.57 μmol g−1 h−1 under visible light irradiation (λ > 420 nm). The superior hydrogen evolution reaction (HER) activity is due to the triazine units, which have high visible light absorption capacity, one-dimensional nanochannels of two-dimensional COFs and synergy with charge mobility. The photoelectrochemical measurements and calculation of density functional theory (DFT) supports the accuracy of the experiment. This work opens an avenue for constructing functional covalent organic frameworks for environmentally relevant critical applications. In addition, the simple synthesis process, excellent activity and high chemical stability indicate that JLNU-COFs are promising photocatalytic hydrogen production materials.

G-C3N4/In2O3 heterojunction films and their excellent photocatalytic performance in fruit preservation and organic dye degradation

We prepared g-C3N4/In2O3 composite films on the wire mesh of stainless steel by a hydrothermal method combined with annealing. XRD, SEM, and XPS results confirmed the heterojunction formation of g-C3N4/In2O3. UV–vis spectroscopy showed that the heterojunction films exhibited enhanced visible light absorption capacity compared with the pristine In2O3 films. Compared with the individual In2O3 films, the PL intensity of the g-C3N4/In2O3 composite films was remarkably reduced, their photocurrent density was significantly increased, and the semicircle in EIS plots was reduced. All the above changes are attributed to the heterojunction formation between g-C3N4 and In2O3. According to our proposed mechanism, photogenerated electrons transfer from g-C3N4 to In2O3 while the holes move in the opposite direction. Therefore, the spatial transfer and separation of photoinduced electrons and holes was achieved. In other words, the recombination efficiency of photogenerated electrons and holes was remarkably suppressed. In photocatalytic RhB degradation, g-C3N4/In2O3 heterojunction films exhibited much higher photocatalytic activity than the pristine In2O3 films. In our self-made photocatalytic fruit-preservation system, these g-C3N4/In2O3 heterojunction films showed excellent fruit preservation ability. Specifically, the bananas remained turquoise green without turning yellow or black spots, even black patches, after a seven-day evaluation period.

AgCl/g-C3N4/Ti-MOFs photocatalytic composite for visible light degradation of xanthate derived from mineral processing industries

Large amounts of xanthate wastewater generated from mineral beneficiation significantly threaten the ecological environment. MOF photocatalysis is considered as a promising method for the removal of xanthate that is environmentally friendly and has high efficiency. However, the defects in MOFs limit their large-scale application due to poor visible light absorption efficiency and stability in water. In this study, a novel composite material composed of g-C3N4/AgCl/Ti-MOFs was prepared, and the catalytic degradation effect of butyl xanthate solution under different catalyst ratios and reaction conditions was investigated. The results showed that the composite could still maintain excellent catalytic performance (degradation rate of 99.5% within 90 min) under xenon light and low dosage. The characterization results showed that this excellent photocatalytic performance could be attributed to the following three points: 1) The material could absorb up to 670 nm visible light absorption capacity; 2) excellent stability was achieved (86% degradation efficiency after six cycles); and 3) the Schottky junctions formed by Ag0 and other materials in the composite increased the transfer rate of e−/h+. The possible photodegradation mechanism was proposed according to UV–vis DRS and trapping experiments.

Synthesis of g-C3N4/HC composite and its visible light catalytic performance

Thermal polymerization prepared g-C3N4/HC composite with good visible light catalytic ability using corn stover and urea as raw materials. The structure of the g-C3N4/HC composite was characterized by XRD, and it was determined that the composite was composed of g-C3N4 and HC. The morphology of the g-C3N4/HC composite was characterized by SEM. g-C3N4 is dispersed in sheet form on HC tubes with a regular porous structure. The degradation efficiency of RhB by g-C3N4/HC reached 99.14% after 70 min irradiation by a 70 W metal halide lamp. The cyclic degradation experiments proved that g-C3N4/HC has good reusability. Compared with g-C3N4, the visible light absorption capacity of g-C3N4/HC is enhanced, and the electron-hole recombination rate is also reduced, which results in the higher photocatalytic capacity of g-C3N4/HC. The free radical trapping experiments confirmed that the hole free radical and the hydroxyl free radical are the primary active substances in the photodegradation reaction.

Rational design of complex quantum dots decorated ceria nanorods for efficient visible-light driven nitrogen fixation

Ceria-based materials, as very active photocatalysts for redox reactions, have been widely investigated, but there are few reports on nitrogen photofixation. Herein, complex dots of Cu2O/Cu-C decorated CeO2 nanorods with an overall photocatalytic nitrogen fixation process are considered. Remarkable photocatalytic performances are obtained by adjusting the band gap structures and surface activity site status. The as-prepared sample has excellent visible light absorption capacity, more photoinduced oxygen defects and excellent nitrogen absorption ability. The ammonia yield is approximately 1124 µmol·gcal−1·h−1 under light irradiation with no sacrificial agents, increasing approximately 8.5 times compared with the Cu-decorated sample. The apparent quantum efficiency at 420 nm is also more than 1.1%. This work may provide a new avenue for the efficient design of photocatalytic materials without any precious metals.

Pillar[5]arene functionalized Au NPs and BiOX (Cl/Br/I) heterojunction constructed the enhanced photo-electrochemical sensor for ultrasensitive detection of serotonin

The functional photoelectric materials based on bismuth oxyhalides (BiOX, X = Cl, Br and I) have been widely used in the field of photo-electrochemistry (PEC) due to their excellent physical, chemical and optical properties. Herein, a series of BiOX nanoflowers conjugated water-soluble pillar[5]arenes functionalized Au (Au@WP5/BiOX) modified PEC sensor are constructed and investigated for the PEC detection of serotonin. Upon exploring the physical properties, such as size, visible light absorption capacity, band gap and impedance, of the three BiOX materials, it is discovered that BiOBr is more effective in detecting 5-HT due to its high redox ability, moderate band gap (∼2.03 eV), and low impedance. BiOBr can provide a high and stable starting photocurrent compared to the other two bismuth oxyhalides. When used in acidic or neutral environments, 5-HT with a positive charge can undergo electrostatic adsorption and host-guest complexation behavior with WP5, which has a negative charge. By using WP5, the recognition ability of the material to 5-HT molecules can be enhanced, and the adsorption of 5-HT molecules on Au@WP5/BiOBr can be accelerated. The local surface plasmon resonance effect (LSPR) of gold nanoparticles (Au NPs) can accelerate the electrochemical reaction rate and charge transfer rate, which ultimately leads to the amplification of the photocurrent signal. As a result, the 5-HT detection sensor based on Au@WP5/BiOBr has a wide detection range from 0.01 to 100 μM and a low detection limit of 3 nM (S/N = 3) compared to other sensors, including Au@WP5/BiOCl and Au@WP5/BiOI. The proposed PEC sensor also exhibits good stability and selectivity, making it a promising strategy for detecting biological small molecules using pillar[5]arene functionalized PEC active materials.

Chemical-Vapor-Deposition-Synthesized Two-Dimensional Non-Stoichiometric Copper Selenide (β-Cu2-xSe) for Ultra-Fast Tetracycline Hydrochloride Degradation under Solar Light.

The high concentration of antibiotics in aquatic environments is a serious environmental issue. In response, researchers have explored photocatalytic degradation as a potential solution. Through chemical vapor deposition (CVD), we synthesized copper selenide (β-Cu2-xSe) and found it an effective catalyst for degrading tetracycline hydrochloride (TC-HCl). The catalyst demonstrated an impressive degradation efficiency of approximately 98% and a reaction rate constant of 3.14 × 10-2 min-1. Its layered structure, which exposes reactive sites, contributes to excellent stability, interfacial charge transfer efficiency, and visible light absorption capacity. Our investigations confirmed that the principal active species produced by the catalyst comprises O2- radicals, which we verified through trapping experiments and electron paramagnetic resonance (EPR). We also verified the TC-HCl degradation mechanism using high-performance liquid chromatography-mass spectrometry (LC-MS). Our results provide valuable insights into developing the β-Cu2-xSe catalyst using CVD and its potential applications in environmental remediation.

Two-dimensional carbon allotrope with remarkable electron mobility and tunable band gap under uniaxial strain engineering

Exploring two-dimensional (2D) materials with unique structures and excellent photoelectric properties has always been the foundation content of carbon-based material science and condensed matter physics research. In this work, on the basis of density functional theory, the structural, mechanical, electrical and optical properties of the pure sp2 hybrid 2D carbon allotropes Orth-C14 and Orth-C16 were comprehensively predicted, and the regulatory mechanism of the uniaxial strain on the stability, elastic mechanics and electronic properties were analysed. Orth-C16 and Orth-C14 are semiconductors and metals with extremely narrow bandgaps, respectively. Interestingly, their electronic properties could be tuned to indirect band gap semiconductors, metals or half-metallic states with Dirac cones by applying uniaxial strain. In addition, the extremely low effective mass (0.009 m0) and remarkable room temperature electron mobility (69,708 cm2V-1s-1) of approximately 70 times greater than that of black phosphorene (1100 ∼ 1140 cm2V-1s-1), as well as the strong absorption capacity of visible light, all of these advantages indicate that Orth-C16 has crucial development potential in the field of electronic information and optoelectronics.

Preparation of direct Z-scheme heterojunction la-doped Bi2WO6/CdS with enhanced visible light absorption and its photocatalytic degradation of antibiotics

In this paper, a novel direct Z-scheme heterojunction La-Bi2WO6/CdS composed of 3-dimensional flower-like Bi2WO6 and hexagonally stacked succulent CdS was successfully designed and synthesized. The morphology, optical properties, element valence and crystal structure of the catalysts were systematically characterized. When the dosage of LBC-40 was 1.0 g/L, the degradation rate of oxytetracycline (OTC, 20 mg/L, pH = 6) was 85.28 %, under low visible light illumination (65 W energy saving lamp) for 120 min and the reaction kinetic constant (0.01336 min−1) was 2.50 and 1.56 times that of pure Bi2WO6 and La-Bi2WO6, respectively. Moreover, La-Bi2WO6/CdS showed good photocatalytic activity for other single antibiotics, mixed antibiotics and antibiotics from different water sources. The photocatalytic activity only decreased by 7.69 % after 3 cycles. Furthermore, the possible photocatalytic degradation pathway and photocatalytic mechanism of OTC were proposed. The excellent photocatalytic performance of La-Bi2WO6/CdS is for that the doping of La3+ and the construction of direct Z-scheme heterojunction enhances the visible light absorption capacity and separation efficiency of photogenerated electron-hole pairs. This paper reports a new method, which can provide a reference for the design and development of visible light responsive photocatalysts with excellent photocatalytic properties.